unit-test-bean-validation

Test Jakarta Bean Validation constraints by configuring a Validator using Validation.buildDefaultValidatorFactory(), then create test instances with valid and invalid data. Call validator.validate() on each instance and assert the ConstraintViolations returned match your expectations for each constraint annotation.

Yes. Jakarta Bean Validation works independently of Spring using the standard Validator API. Build a default validator factory, instantiate test beans with constraint annotations, and validate them directly in isolated JUnit 5 tests without any Spring context or container overhead.

Create a test bean with your custom @Constraint annotation, build a Validator from the default factory, and validate test instances that trigger your custom validator logic. Assert ConstraintViolations contain the expected violation messages from your constraint implementation.

Test cross-field validations by creating test instances with combinations of field values that satisfy or violate your multi-field constraint rules. Use the Validator to check each case and assert violations occur only when the cross-field constraint condition fails.

Yes. All standard Jakarta Bean Validation annotations including @Min, @Max, @Email, and @NotNull function in unit tests using the default Validator, independent of any framework or context, ensuring fast, deterministic constraint verification.

Isolated unit tests for constraints are faster, deterministic, and don't require loading application context or databases. They verify constraint logic directly without external dependencies, catch validation bugs early, and run in milliseconds compared to integration test overhead.